Current status of brachytherapy in cancer treatment - short overview

Access to brachytherapy treatment for cervical cancer management in Africa

Background and purpose

Cervical cancer is an important public health issue with a high incidence and death rate in Africa. It is mostly treated with Brachytherapy as the gold standard but its access is limited. This study set out to investigate the distribution and accessibility of brachytherapy units in Africa for the treatment of cervical cancer, and to provide some recommendations for increasing the quantity and accessibility of such equipment throughout the continent.

Materials and methods

The International Atomic Energy Agency's Division of Human Health's Directory for radiotherapy Centers (DIRAC) was the principal source of data for this study. The number of brachytherapy equipment in the 54 African countries was obtained from the DIRAC database. The number of cervical cancer cases was obtained from the GLOBOCAN 2022 database, and country's income was calculated using the Gross Domestic Product (GDP) per capita from the global economics database. All of these searches were conducted in February 2024.

Results

Africa exhibited a greater number of cervical cancer cases. A total of one hundred (100) brachytherapy units were present across 84 radiotherapy centres spanning 20 African countries. Egypt and South Africa each possess 23 units, which accounts for 46% of the overall quantity. With just two brachytherapy facilities, Nigeria had the most cervical cancer cases. A significant quantity of brachytherapy unit was situated in countries of northern Africa. The quantity of these units varied among countries, from those without any to those with many, and was not only influenced by GDP per capita.

Conclusion

Due to the rising incidence of cervical cancer in Africa, the number of brachytherapy equipment was woefully inadequate. Consequently, Africa requires partnerships and financial support to facilitate the quantity and accessibility of brachytherapy services. This will enable the provision of thorough and holistic care to patients and enhance their quality of life.

Melanoma Cells from Different Patients Differ in Their Sensitivity to Alpha Radiation-Mediated Killing, Sensitivity Which Correlates with Cell Nuclei Area and Double Strand Breaks

Background/Objective: In this study, for the first time, we examined and compared the sensitivity of four patient-derived cutaneous melanoma cell lines to alpha radiation in vitro and analyzed it in view of cell nucleus area and the formation of double-strand breaks (DSB). Melanoma cells sensitivity to alpha radiation was compared to photon radiation effects. Furthermore, we compared the sensitivity of the melanoma cells to squamous cell carcinoma. Methods: Human melanoma cell lines YDFR.C, DP.C, M12.C, and M16.C, and the squamous cell carcinoma cell line, CAL 27, were irradiated in vitro using Americium-241 as alpha-particle source. Cells were irradiated with doses of 0 to 2.8 gray (Gy). Cell viability, DNA DSB, and nuclear size were measured. Results: 1. Alpha radiation caused death and proliferation arrest of all four melanoma cell lines, but inter-tumor heterogeneity was observed. 2. The most sensitive cell line (DP.C) had a significantly larger nucleus area (408 µm2) and the highest mean number of DSB per cell (9.61) compared to more resistant cells. 3. The most resistant cell, M16.C, had a much lower nucleus area (236.99 µm2) and DSB per cell (6.9). 4. Alpha radiation was more lethal than photon radiation for all melanoma cells. 5. The SCC cell, CAL 27, was more sensitive to alpha radiation than all melanoma cells but had a similar number of DSB (6.67) and nucleus size (175.49 µm2) as the more resistant cells. 6. The cytotoxic effect of alpha radiation was not affected by proliferation arrest after serum starvation. 7. Killing of cells by alpha radiation was marginally elevated by ATR or topoisomerase 1 inhibition. Conclusions: This study demonstrates that various human melanoma cells can be killed by alpha radiation but exhibit variance in sensitivity to alpha radiation. Alpha radiation applied using the Intra-tumoral Diffusing alpha-emitters Radiation Therapy (Alpha DaRT) methodology may serve as an efficient treatment for human melanoma.

Dose escalation with stereotactic body radiotherapy for cervical cancer treatment

BACKGROUND

Dose escalation with brachytherapy after pelvic irradiation is standard for treating cervical cancer. Its application can be impossible for some patients. Dose escalation with SBRT is widely used with high local control and acceptable toxicity rates in different body parts. The study enrolled patients who underwent SBRT treatment for dose escalation in the cervix.

METHODS

Patients who were pathologically diagnosed and treated with cervical SBRT after definitive CRT were included in the study. A total of 30 Gy in 5 fractions for the high-risk volume was prescribed. The first response evaluation was performed three months after the completion of treatment. Treatment toxicity was documented according to the RTOG-EORTC scale. Oncological outcomes and toxicity were assessed.

RESULTS

Between 02.2019 and 05.2023, 40 patients were treated with an SBRT boost after pelvic irradiation. The median follow-up time was 16 months (7-44 months). The median HR CTV was 47 cc (8,3-168,2 cc). There were 39 patients who achieved a complete response and one who achieved a partial response in the third month after treatment. There were two local or two regional recurrences. The 1-year metastasis-free survival was 88%, and the 1-year progression-free survival was 88%. During the follow-up period, one grade 3 gastrointestinal side effect was observed.

CONCLUSIONS

SBRT which has low toxicity and reasonable locoregional control rates in a short follow-up period, may be an option for dose escalation in brachytherapy-ineligible cervical cancer patients.

A Review of Artificial Intelligence in Brachytherapy

Artificial intelligence (AI) has the potential to revolutionize brachytherapy's clinical workflow. This review comprehensively examines the application of AI, focusing on machine learning and deep learning, in facilitating various aspects of brachytherapy. We analyze AI's role in making brachytherapy treatments more personalized, efficient, and effective. The applications are systematically categorized into seven categories: imaging, preplanning, treatment planning, applicator reconstruction, quality assurance, outcome prediction, and real-time monitoring. Each major category is further subdivided based on cancer type or specific tasks, with detailed summaries of models, data sizes, and results presented in corresponding tables. This review offers insights into the current advancements, challenges, and the impact of AI on treatment paradigms, encouraging further research to expand its clinical utility.

Evaluation and improvement of the safety of 3D-printed template assisted intracavitary/interstitial brachytherapy for cervical cancer using repeat FMEA

BACKGROUND AND PURPOSE

3D-printed templates are used in intracavitary/interstitial brachytherapy (3DP-IC/IS) for locally advanced cervical cancer (LACC). We applied failure mode and effects analysis (FMEA) twice in one year to improve 3DP-IC/IS safety.

MATERIALS AND METHODS

A risk assessment group was established. We created a process map for 3DP-IC/IS procedures, identifying potential failure modes (FMs) and evaluating occurrence (O), detectability (D), severity (S), and risk priority number (RPN = O*D*S). High RPN values identified high-risk FMs, and quality control (QC) methods were determined by root cause analysis. A second FMEA was performed a year later.

RESULTS

The 3DP-IC/IS process included 10 main steps, 48 subprocesses, and 54 FMs. Initial RPN values ranged from 4.50 to 171.00 (median 50.50; average 52.18). Ten high-risk FMs were identified: (1) unreasonable needle track design (171.00/85.50), (2) noncoplanar needle label identification failure (126.00/64.00), (3) template model reconstruction failure (121.50/62.50), (4) improper gauze filling (112.00/60.25), (5) poor needle position (112.00/52.50). QC interventions lowered all high-risk RPN values during the second assessment.

CONCLUSIONS

A feasible 3DP-IC/IS process was proposed. Staff training, automatic needle path planning, insertion guidance diagrams, template checking, system commissioning, and template design improvements effectively enhanced process safety.

Three-dimensional trans-rectal and trans-abdominal ultrasound image fusion for the guidance of gynecologic brachytherapy procedures: a proof of concept study

High dose-rate brachytherapy is a treatment technique for gynecologic cancers where intracavitary applicators are placed within the patient's pelvic cavity. To ensure accurate radiation delivery, localization of the applicator at the time of insertion is vital. This study proposes a novel method for acquiring, registering, and fusing three-dimensional (3D) trans-abdominal and 3D trans-rectal ultrasound (US) images for visualization of the pelvic anatomy and applicators during gynecologic brachytherapy. The workflow was validated using custom multi-modal pelvic phantoms and demonstrated during two patient procedures. Experiments were performed for three types of intracavitary applicators: ring-and-tandem, ring-and-tandem with interstitial needles, and tandem-and-ovoids. Fused 3D US images were registered to magnetic resonance (MR) and computed tomography (CT) images for validation. The target registration error (TRE) and fiducial localization error (FLE) were calculated to quantify the accuracy of our fusion technique. For both phantom and patient images, TRE and FLE across all modality registrations (3D US versus MR or CT) resulted in mean ± standard deviation of 4.01 ± 1.01 mm and 0.43 ± 0.24 mm, respectively. This work indicates proof of concept for conducting further clinical studies leveraging 3D US imaging as an accurate, accessible alternative to advanced modalities for localizing brachytherapy applicators.

COMIRI - COMplexity Index of interventional Radiotherapy (brachytherapy) Implants: assessment of procedures based on type, equipment, and team

Historically, several classification systems have been used for brachytherapy, and they were based on the type of clinical purpose, type of implant and timing of the implant, dose-rate, and type of loading for treatment delivery. However, over the last decades, there have been some major technological advancements, including the introduction of image-guidance and possibility to modulate the dose delivered, which have led several authors (in order to highlight the differences between old technique and new approach) to label it in a different way by replacing "brachytherapy" with "interventional radiotherapy". Modern interventional procedures involve several key aspects, which contribute to the complexity of implant phase, such as implant type, imaging used during the procedure, and role of multi-disciplinary team in operating room. By assigning scores to these procedural elements, it is possible to classify the procedure's complexity using a COMIRI classification (COMplexity Index of interventional Radiotherapy Implants). The aim of the COMIRI classification system is to appropriately highlight the need for suitable resources based on the complexity level of different procedures in terms of personnel expertise, equipment availability, and multi-disciplinary teamwork.

Therapeutic prostate cancer interventions: a systematic review on pubic arch interference and needle positioning errors

INTRODUCTION

This study focuses on the quantification of and current guidelines on the hazards related to needle positioning in prostate cancer treatment: (1) access restrictions to the prostate gland by the pubic arch, so-called Pubic Arch Interference (PAI) and (2) needle positioning errors. Next, we propose solution strategies to mitigate these hazards.

METHODS

The literature search was executed in the Embase, Medline ALL, Web of Science Core Collection*, and Cochrane Central Register of Controlled Trials databases.

RESULTS

The literature search resulted in 50 included articles. PAI was reported in patients with various prostate volumes. The level of reported PAI varied between 0 and 22.3 mm, depending on the patient's position and the measuring method. Low-Dose-Rate Brachytherapy induced the largest reported misplacement errors, especially in the cranio-caudal direction (up to 10 mm) and the largest displacement errors were reported for High-Dose-Rate Brachytherapy in the cranio-caudal direction (up to 47 mm), generally increasing over time.

CONCLUSIONS

Current clinical guidelines related to prostate volume, needle positioning accuracy, and maximum allowable PAI are ambiguous, and compliance in the clinical setting differs between institutions. Solutions, such as steerable needles, assist in mitigating the hazards and potentially allow the physician to proceed with the procedure.This systematic review was performed in accordance with the PRISMA guidelines. The review was registered at Protocols.io (DOI: dx.doi.org/10.17504/protocols.io.6qpvr89eplmk/v1).

RNA biomarkers in cancer therapeutics: The promise of personalized oncology

Cancer therapy is a rapidly evolving and constantly expanding field. Current approaches include surgery, conventional chemotherapy and novel biologic agents as in immunotherapy, that together compose a wide armamentarium. The plethora of choices can, however, be clinically challenging in prescribing the most suitable treatment for any given patient. Fortunately, biomarkers can greatly facilitate the most appropriate selection. In recent years, RNA-based biomarkers have proven most promising. These molecules that range from small noncoding RNAs to protein coding gene transcripts can be valuable in cancer management and especially in cancer therapeutics. Compared to their DNA counterparts which are stable throughout treatment, RNA-biomarkers are dynamic. This allows prediction of success prior to treatment start and can identify alterations in expression that could reflect response. Moreover, improved nucleic acid technology allows RNA to be extracted from practically every biofluid/matrix and evaluated with exceedingly high analytic sensitivity. In addition, samples are largely obtained by minimally invasive procedures and as such can be used serially to assess treatment response real-time. This chapter provides the reader insight on currently known RNA biomarkers, the latest research employing Artificial Intelligence in the identification of such molecules and in clinical decisions driving forward the era of personalized oncology.

Three-Dimensional-Printed Template-Guided Radioactive Seed Brachytherapy via a Submental Approach for Recurrent Base of Tongue and Floor of Mouth Cancer

Background

This study assessed clinical outcomes of three-dimensional-printed template (3DPT)-guided radioactive seed brachytherapy (RSBT) via a submental approach for recurrent base of tongue and floor of mouth cancer.

Methods

Thirty-one patients with recurrent lingual and floor of mouth squamous cell carcinoma after surgery and radiotherapy were treated with 3DPT-guided RSBT from 2015 to 2022. Seeds were implanted through a submental approach guided by 3DPTs. Local control (LC), overall survival (OS), disease control (DC) and quality of life (QOL) were evaluated.

Results

The median follow-up was 13.7 months. The 1-, 3- and 5-year LC rates were 66.1%, 66.1%, and 55.1% respectively. The 1-, 3- and 5-year OS rates were 63.4%, 33.4%, and 8.3%. The 1-, 3- and 5-year DC rates were 37.8%, 26.5%, and 21.2%. Univariate analysis showed tumor size significantly affected LC (P = 0.031). The presence of extraterritorial lesions affected DC and OS on multivariate analysis (P < 0.01). QOL improved significantly in domains of pain, swallowing, chewing, taste, and emotion after treatment compared to baseline. Four patients (13%) developed necrosis and osteoradionecrosis.

Conclusions

3DPT-guided submental RSBT provided favorable LC and QOL for recurrent tongue/floor of mouth cancer with minimal toxicity; moreover, severe toxicity should be noted.

A Novel Positive-Contrast Magnetic Resonance Imaging Line Marker for High-Dose-Rate (HDR) MRI-Assisted Radiosurgery (MARS)

Magnetic resonance imaging (MRI) can facilitate accurate organ delineation and optimal dose distributions in high-dose-rate (HDR) MRI-Assisted Radiosurgery (MARS). Its use for this purpose has been limited by the lack of positive-contrast MRI markers that can clearly delineate the lumen of the HDR applicator and precisely show the path of the HDR source on T1- and T2-weighted MRI sequences. We investigated a novel MRI positive-contrast HDR brachytherapy or interventional radiotherapy line marker, C4:S, consisting of C4 (visible on T1-weighted images) complexed with saline. Longitudinal relaxation time (T1) and transverse relaxation time (T2) for C4:S were measured on a 1.5 T MRI scanner. High-density polyethylene (HDPE) tubing filled with C4:S as an HDR brachytherapy line marker was tested for visibility on T1- and T2-weighted MRI sequences in a tissue-equivalent female ultrasound training pelvis phantom. Relaxivity measurements indicated that C4:S solution had good T1-weighted contrast (relative to oil [fat] signal intensity) and good T2-weighted contrast (relative to water signal intensity) at both room temperature (relaxivity ratio > 1; r2/r1 = 1.43) and body temperature (relaxivity ratio > 1; r2/r1 = 1.38). These measurements were verified by the positive visualization of the C4:S (C4/saline 50:50) HDPE tube HDR brachytherapy line marker on both T1- and T2-weighted MRI sequences. Orientation did not affect the relaxivity of the C4:S contrast solution. C4:S encapsulated in HDPE tubing can be visualized as a positive line marker on both T1- and T2-weighted MRI sequences. MRI-guided HDR planning may be possible with these novel line markers for HDR MARS for several types of cancer.

Radiation Safety Assessment in Prostate Cancer Treatment: A Predictive Approach for I-125 Brachytherapy

This study uses Monte Carlo simulation and experimental measurements to develop a predictive model for estimating the external dose rate associated with permanent radioactive source implantation in prostate cancer patients. The objective is to estimate the accuracy of the patient's external dose rate measurement. First, I-125 radioactive sources were implanted into Mylar window water phantoms to simulate the permanent implantation of these sources in patients. Water phantom experimental measurement was combined with Monte Carlo simulation to develop predictive equations, whose performance was verified against external clinical data. The model's accuracy in predicting the external dose rate in patients with permanently implanted I-125 radioactive sources was high (R2 = 0.999). A comparative analysis of the experimental measurements and the Monte Carlo simulations revealed that the maximum discrepancy between the measured and calculated values for the water phantom was less than 5.00%. The model is practical for radiation safety assessments, enabling the evaluation of radiation exposure risks to individuals around patients with permanently implanted I-125 radioactive sources.

Updated Trends in Cervical Cancer Brachytherapy Utilization and Disparities in the United States From 2004 to 2020

PURPOSE

Lower brachytherapy utilization for cervical cancer patients is associated with decreased survival. This study examines more recent trends in brachytherapy utilization from 2004 to 2020 to assess any trend reversal after awareness increased regarding the importance of brachytherapy.

METHODS AND MATERIALS

This study analyzed data from the National Cancer Database of patients with Federation of Gynecology and Obstetrics (FIGO) IB to IVA cervical cancer treated with radiation therapy between 2004 and 2020. To compare brachytherapy utilization over time, 2- to 3-year categories were created to account for potential variation seen in individual years. A multivariate log binomial regression with robust variance was used to estimate the incidence rate ratio (IRR) of brachytherapy utilization in each year category in reference to the 2004-2006 category. Additionally, risk factors for brachytherapy utilization were identified.

RESULTS

Overall brachytherapy utilization for cervical cancer increased from 54.9% in 2004 to 75.7% in 2020. Compared with 2004 to 2006 when rates of utilization totaled 55.2%, brachytherapy utilization significantly increased to 63.4% in 2011 to 2014 (IRR, 1.15; 95% CI, 1.11-1.19), 66.0% in 2015 to 2017 (1.20 [1.16-1.23]), and 76.0% in 2018 to 2020 (1.38 [1.34-1.42]). Sociodemographic factors associated with lower brachytherapy utilization included Black race (0.94 [0.92-0.97]), Hispanic ethnicity (0.92 [0.90-0.95]), and age >59 years (age ≥60-69: 0.96 [0.94-0.98]; age ≥70-79: 0.89 [0.87-0.92]; age ≥80: 0.73 [0.69-0.77]). Positive predictors of brachytherapy utilization included having insurance (IRR, 1.11; 95% CI, 1.07-1.14).

CONCLUSIONS

In patients with FIGO IB-IVA cervical cancer treated with radiation therapy from 2004 to 2020, brachytherapy utilization has increased during the past decade. These results are encouraging given the known benefit to cause-specific survival and overall survival provided by brachytherapy treatment and indicate a reversal in the trend of declining brachytherapy noted previously. Concerns related to disparities by race, ethnicity, and insurance status require further interventions.

Time-action and patient experience analyses of locally advanced cervical cancer brachytherapy

BACKGROUND AND PURPOSE

Although MRI-based image guided adaptive brachytherapy (IGABT) for locally advanced cervical cancer (LACC) has resulted in favorable outcomes, it can be logistically complex and time consuming compared to 2D image-based brachytherapy, and both physically and emotionally intensive for patients. This prospective study aims to perform time-action and patient experience analyses during IGABT to guide further improvements.

MATERIALS AND METHODS

LACC patients treated with IGABT were included for the time-action (56 patients) and patient experience (29 patients) analyses. Times per treatment step were reported on a standardized form. For the patient experience analysis, a baseline health status was established with the EQ-5D-5L questionnaire and the perceived pain, anxiety and duration for each treatment step were assessed with the NRS-11.

RESULTS

The median total procedure time from arrival until discharge was 530 (IQR: 480-565) minutes. Treatment planning (delineation, reconstruction, optimization) required the most time and took 175 (IQR: 145-195) minutes. Highest perceived pain was reported during applicator removal and treatment planning, anxiety during applicator removal, and duration during image acquisition and treatment planning. Perceived pain, anxiety and duration were correlated. Higher pre-treatment pain and anxiety scores were associated with higher perceived pain, anxiety and duration.

CONCLUSION

This study highlights the complexity, duration and impact on patient experience of the current IGABT workflow. Patient reported pre-treatment pain and anxiety can help identify patients that may benefit from additional support. Research and implementation of measures aiming at shortening the overall procedure duration, which may include logistical, staffing and technological aspects, should be prioritized.

Brachytherapy on-a-chip: a clinically-relevant approach for radiotherapy testing in 3d biology

We describe the first microfluidic device for in vitro testing of brachytherapy (BT), with applications in translational cancer research. Our PDMS-made BT-on-chip system allows highly precise manual insertion of clinical BT seeds, reliable dose calculation using standard clinically-used TG-43 formalism and easy culture of naturally hypoxic spheroids in less than 3 days, thereby increasing the translational potential of the device. As the BT-on-chip platform is designed to be versatile, we showcase three different gold-standard post-irradiation bioassays and recapitulate, for the first time on-chip, key clinical observations such as dose rate effect and hypoxia-induced radioresistance. Our results suggest that BT-on-chip can be used to safely and efficiently integrate BT and radiotherapy to translational research and drug development pipelines, without expensive equipment or complex workflows.

Phantom study of a fully automatic radioactive seed placement robot for the treatment of skull base tumours

BACKGROUND

Interstitial brachytherapy is a form of intensive local irradiation that facilitates the effective protection of surrounding structures and the preservation of organ functions, resulting in a favourable therapeutic response. As surgical robots can perform needle placement with a high level of accuracy, our team developed a fully automatic radioactive seed placement robot, and this study aimed to evaluate the accuracy and feasibility of fully automatic radioactive seed placement for the treatment of tumours in the skull base.

METHODS

A fully automatic radioactive seed placement robot was established, and 4 phantoms of skull base tumours were built for experimental validation. All the phantoms were subjected to computed tomography (CT) scans. Then, the CT data were imported into the Remebot software to design the preoperative seed placement plan. After the phantoms were fixed in place, navigation registration of the Remebot was carried out, and the automatic seed placement device was controlled to complete the needle insertion and particle placement operations. After all of the seeds were implanted in the 4 phantoms, postoperative image scanning was performed, and the results were verified via image fusion.

RESULTS

A total of 120 seeds were implanted in 4 phantoms. The average error of seed placement was (2.51 ± 1.44) mm.

CONCLUSION

This study presents an innovative, fully automated radioactive particle implantation system utilizing the Remebot device, which can successfully complete automated localization, needle insertion, and radioactive particle implantation procedures for skull base tumours. The phantom experiments showed the robotic system to be reliable, stable, efficient and safe. However, further research on the needle-soft tissue interaction and deformation mechanism of needle puncture is still needed.

Brachytherapy and 3D printing for skin cancer: A review paper

Brachytherapy is a type of radiation therapy, in which a radiation source is placed directly or close to a tumor. It is commonly used to treat skin cancer, and enables precise irradiation treatment of affected area (planning target volume - PTV) while minimizing exposure dose to surrounding healthy tissue (organs at risk - OARs). Recently, the use of 3D printing has begun revolutionizing brachytherapy, as it allows manufacturing of custom-designed applicators for unique shape of skin topography, tumor, and surrounding tissues. Outcome of the combination of 3D printing and brachytherapy has several advantages over traditional treatment planning methods. Some of the advantages are intuitive, whereas others can be concluded from a literature overview as follows: 1) Possibility of developing patient-specific applicators that precisely match the shape of tumor area; 2) Reduction of the time required for applicator production, especially when custom-made devices are needed; 3) Reduction of manufacturing costs; 4) Treatment procedures improvement; 5) Improvement of safety measures accelerated by the development of smart materials (e.g., polymer filaments with admixture of heavy elements); 6) Possibility of nearly instant adjustment into tumor treatment (applicators can be changed as the tumor is changing its shape); and 7) Applicators designed to securely fit to treatment area to hold radioactive source always in the same place for each fraction. Consequently, tumor-provided dose is accurate and leads to effective treatment. In this review paper, we investigated the current state-of-the-art of the application of 3D printing in brachytherapy. A number of existing reports were chosen and reviewed in terms of printing technology, materials used, treatment effectiveness, and fabrication protocols. Furthermore, the development of future directions that should be considered by collaborative teams bridging different fields of science, such as medicine, physics, chemistry, and material science were summarized. With the indicated topics, we hope to stimulate the innovative progress of 3D printing technology in brachytherapy.

177Lu-Labeled Iron Oxide Nanoparticles Functionalized with Doxorubicin and Bevacizumab as Nanobrachytherapy Agents against Breast Cancer

The use of conventional methods for the treatment of cancer, such as chemotherapy or radiotherapy, and approaches such as brachytherapy in conjunction with the unique properties of nanoparticles could enable the development of novel theranostic agents. The aim of our current study was to evaluate the potential of iron oxide nanoparticles, coated with alginic acid and polyethylene glycol, functionalized with the chemotherapeutic agent doxorubicin and the monoclonal antibody bevacizumab, to serve as a nanoradiopharmaceutical agent against breast cancer. Direct radiolabeling with the therapeutic isotope Lutetium-177 (177Lu) resulted in an additional therapeutic effect. Functionalization was accomplished at high percentages and radiolabeling was robust. The high cytotoxic effect of our radiolabeled and non-radiolabeled nanostructures was proven in vitro against five different breast cancer cell lines. The ex vivo biodistribution in tumor-bearing mice was investigated with three different ways of administration. The intratumoral administration of our functionalized radionanoconjugates showed high tumor accumulation and retention at the tumor site. Finally, our therapeutic efficacy study performed over a 50-day period against an aggressive triple-negative breast cancer cell line (4T1) demonstrated enhanced tumor growth retention, thus identifying the developed nanoparticles as a promising nanobrachytherapy agent against breast cancer.

Embedding expertise knowledge into inverse treatment planning for low-dose-rate brachytherapy of hepatic malignancies

BACKGROUND

Leveraging the precision of its radiation dose distribution and the minimization of postoperative complications, low-dose-rate (LDR) permanent seed brachytherapy is progressively adopted in addressing hepatic malignancies.

PURPOSE

The present study endeavors to devise a sophisticated treatment planning system (TPS) to optimize LDR brachytherapy for hepatic lesions.

METHODS

Our TPS encompasses four integral modules: multi-organ segmentation, seed distribution initialization, puncture pathway selection, and inverse dose planning. By amalgamating an array of deep learning models, the segmentation module proficiently labels 17 discrete abdominal targets within the images. We introduce a knowledge-based seed distribution initialization methodology that discerns the most analogous tumor shape in the reference treatment plan from the knowledge base. Subsequently, the seed distribution from the reference plan is transmuted to the current case, thus establishing seed distribution initialization. Furthermore, we parameterize the puncture needles and seeds, while concurrently constraining the puncture needle angle through the employment of a virtual puncture panel to augment planning algorithm efficiency. We also presented a user interface that includes a range of interactive features, seamlessly integrated with the treatment planning generation function.

RESULTS

The multi-organ segmentation module, which is trained by 50 cases of in-house CT scans and 694 cases of publicly available CT scans, achieved average Dice of 0.80 and Hausdorff distance of 5.2 mm in testing datasets. The results demonstrate that knowledge-based initialization exhibits a marked enhancement in expediting the convergence rate. Our TPS also demonstrates a dominant advantage in dose-volume-histogram criteria and execution time in comparison to commercial TPS.

CONCLUSION

The study proposes an innovative treatment planning system for low-dose-rate permanent seed brachytherapy for hepatic malignancies. We show that the generated treatment plans meet clinical requirement.

High-dose rate endorectal brachytherapy for rectal cancer: A state-of-the-art review

Rectal cancer is a common malignancy that requires multidisciplinary treatment. By utilizing the dose-response relationship in rectal cancer radiotherapy, increasing the radiotherapy dose can improve clinical complete remission rates. High-dose rate endorectal brachytherapy (HDREBT) is a novel technique that delivers high doses of radiotherapy directly to the tumor via an endorectal applicator, sparing the adjacent normal tissues from excessive radiation exposure. HDREBT includes contact X-ray brachytherapy and high-dose-rate intracavitary brachytherapy. We introduce the latest developments in applicators and imaging techniques for HDREBT in rectal cancer and summarize the current evidence on the efficacy, safety, and feasibility of HDREBT as a neoadjuvant, definitive, or palliative treatment option for all stages of rectal cancer patients. We also discuss the potential advantages and challenges of HDREBT in achieving organ preservation and improving the quality of life of rectal cancer patients. HDREBT has shown promising results in achieving high complete response rates, enabling nonoperative management, improving organ preservation rates, and providing effective palliation in rectal cancer patients. More studies are needed to optimize its dose and fractionation schemes in different clinical scenarios.

Monte Carlo-based optimization of glioma capsule design for enhanced brachytherapy

The use of radiotherapy in tumor treatment has become increasingly prominent and has emerged as one of the main tools for treating malignant tumors. Current radiation therapy for glioma employs 125I seeds for brachytherapy, which cannot be combined with radiotherapy and chemotherapy. To address this limitation, this paper proposes a dual-microcavity capsule structure that integrates radiotherapy and chemotherapy. The Monte Carlo simulation method is used to simulate the structure of the dual-microcavity capsule with a 125I liquid radioactive source. Based on the simulation results, two kinds of dual-microcavity capsule structures are optimized, and the optimized dual-microcavity capsule structure is obtained. Finally, the dosimetric parameters of the two optimized dual-microcavity capsule structures are analyzed and compared with those of other 125I seeds. The optimization tests show that the improved dual-capsule dual-microcavity structure is more effective than the single-capsule dual-microcavity structure. At an activity of 5 mCi, the average absorbed dose rate is 71.2 cGy/h in the center of the optimized dual-capsule dual-microcavity structure and 45.8 cGy/h in the center of the optimized single-capsule dual-microcavity structure. Although the radial dose function and anisotropy function exhibite variations from the data of other 125I seeds, they are generally similar. The absorbed dose rate decreases exponentially with increasing distance from the center of the capsule, which can reduce the damage to the surrounding tissues and organs while increasing the dose. The capsule structure has a better irradiation effect than conventional 125I seeds and can accomplish long-term, stable, low-dose continuous irradiation to form local high-dose radiation therapy for glioma.

Developing an AI-Assisted Educational Chatbot for Radiotherapy Using the IBM Watson Assistant Platform

Objectives: This study aims to make radiotherapy knowledge regarding healthcare accessible to the general public by developing an AI-powered chatbot. The interactive nature of the chatbot is expected to facilitate better understanding of information on radiotherapy through communication with users. Methods: Using the IBM Watson Assistant platform on IBM Cloud, the chatbot was constructed following a pre-designed flowchart that outlines the conversation flow. This approach ensured the development of the chatbot with a clear mindset and allowed for effective tracking of the conversation. The chatbot is equipped to furnish users with information and quizzes on radiotherapy to assess their understanding of the subject. Results: By adopting a question-and-answer approach, the chatbot can engage in human-like communication with users seeking information about radiotherapy. As some users may feel anxious and struggle to articulate their queries, the chatbot is designed to be user-friendly and reassuring, providing a list of questions for the user to choose from. Feedback on the chatbot's content was mostly positive, despite a few limitations. The chatbot performed well and successfully conveyed knowledge as intended. Conclusions: There is a need to enhance the chatbot's conversation approach to improve user interaction. Including translation capabilities to cater to individuals with different first languages would also be advantageous. Lastly, the newly launched ChatGPT could potentially be developed into a medical chatbot to facilitate knowledge transfer.

Complication and response assessment of high-dose-rate endorectal brachytherapy boost in neo-adjuvant chemoradiotherapy of locally advanced rectal cancer with long-term outcomes

Purpose

To identify efficacy, complication, and pathologic response of high-dose-rate endorectal brachytherapy (HDR-BRT) boost in neo-adjuvant chemoradiotherapy (nCRT) of locally advanced rectal cancer.

Material and methods

Forty-four patients who met eligibility criteria were included in this non-randomized comparative study. Control group was recruited retrospectively. nCRT (50.40 Gy/28 fr. plus capecitabine 825 mg/m² twice daily) was administered to both groups before surgery. In the case group, HDR-BRT (8 Gy/2 fr.) was supplemented after chemoradiation. Surgery was done 6-8 weeks after completion of neo-adjuvant therapy. Pathologic complete response (pCR) was the study's primary endpoint.

Results

From 44 patients in the case and control groups, pCR was 11 (50%) and 8 (36.4%), respectively (p = 0.27). According to Ryan's grading system, tumor regression grade (TRG) TRG1, TRG2, and TRG3 were 16 (72.7%), 2 (9.1%), and 4 (18.2%) in the case, and 10 (45.5%), 7 (31.8%), and 5 (22.7%) in the control group (p = 0.118). T down-staging was found in 19 (86.4%) and 13 (59.1%) patients in the case and control groups, respectively. No grade > 2 toxicity was identified in both the groups. Organ preservation was achieved in 42.8% and 15.3% in the case and control arm (p = 0.192). In the case group, 8-year overall survival (OS) and disease-free survival (DFS) were 89% (95% CI: 73-100%) and 78% (95% CI: 58-98%), respectively. Our study did not reach median OS and median DFS.

Conclusions

Treatment schedule was well-tolerated, and neo-adjuvant HDR-BRT could achieve better T down-staging as a boost comparing with nCRT, without significant complication. However, the optimal dose and fractions in the context of HDR-BRT boost needs further studies.

Use of Thermoluminescence Dosimetry for QA in High-Dose-Rate Skin Surface Brachytherapy with Custom-Flap Applicator

Surface brachytherapy (BT) lacks standard quality assurance (QA) protocols. Commercially available treatment planning systems (TPSs) are based on a dose calculation formalism that assumes the patient is made of water, resulting in potential deviations between planned and delivered doses. Here, a method for treatment plan verification for skin surface BT is reported. Chips of thermoluminescent dosimeters (TLDs) were used for dose point measurements. High-dose-rate treatments were simulated and delivered through a custom-flap applicator provided with four fixed catheters to guide the Iridium-192 (Ir-192) source by way of a remote afterloading system. A flat water-equivalent phantom was used to simulate patient skin. Elekta TPS Oncentra Brachy was used for planning. TLDs were calibrated to Ir-192 through an indirect method of linear interpolation between calibration factors (CFs) measured for 250 kV X-rays, Cesium-137, and Cobalt-60. Subsequently, plans were designed and delivered to test the reproducibility of the irradiation set-up and to make comparisons between planned and delivered dose. The obtained CF for Ir-192 was (4.96 ± 0.25) μC/Gy. Deviations between measured and TPS calculated doses for multi-catheter treatment configuration ranged from -8.4% to 13.3% with an average of 0.6%. TLDs could be included in clinical practice for QA in skin BT with a customized flap applicator.

Investigation of Radiochromic Film Use for Source Position Verification through a LINAC On-Board Imager (OBI)

Background and Objectives: Quality assurance is an integral part of brachytherapy. Traditionally, radiographic films have been used for source position verification, however, in many clinics, computerized tomography simulators have replaced conventional simulators, and computerized radiography systems have replaced radiographic film processing units. With these advances, the problem of controlling source position verification without traditional radiographic films and conventional simulators has appeared. Materials and Methods: In this study, we investigated an alternative method for source position verification for brachytherapy applications. Source positions were evaluated using Gafchromic™ RTQA2 and EBT3 film and visually compared to exposed RTQA radiochromic film when using a Nucletron Oldelft Simulix HP conventional simulator and a Gammamed 12-i brachytherapy device for performance evaluation. Gafchromic film autoradiography was performed with a linear accelerator (LINAC) on-board imager (OBI). Radiochromic films are very suitable for evaluation by visual inspection with a LINAC OBI. Results: The results showed that this type of low-cost, easy-to-find material can be used for verification purposes under clinical conditions. Conclusions: It can be concluded that source-position quality assurance may be performed through a LINAC OBI device.

Cyclotron production of 103Pd using a liquid target

INTRODUCTION

In this work, we present the first feasibility study on the production of the medically important radionuclide ¹⁰³Pd via the ¹⁰³Rh(p,n)¹⁰³Pd reaction by cyclotron irradiation of a liquid target. Using a liquid target removes the time consuming and complex dissolution process of rhodium post-irradiation due to its chemically inactive nature and thereby will improve the accessibility of this radioisotope.

METHODS

Liquid targets made from Rh(NO₃)₃·×H₂O salt dissolved in de-ionized water were irradiated using a 12 MeV beam at the TR13 cyclotron at TRIUMF, Vancouver.

RESULTS

A maximum EOB activity of 1.03 ± 0.05 MBq was achieved with the tested conditions, sufficient for basic radiochemistry studies. An effective separation method using anion exchange chromatography is reported using 1 M HNO₃ as an eluent for rhodium (90.1 ± 2.1 % recovery) and a 1:1 mixture of 0.5 M NH₃ + NH₄Cl palladium eluent (103.8 ± 2.3 % recovery). The solution showed good in-target pressure stability. However, the production efficiency decreased significantly with higher solution concentrations and irradiation lengths which puts into question the scaling potential of this method.

CONCLUSION

This proof-of-concept study has demonstrated the potential for using liquid targets as complementary production method of ¹⁰³Pd for research purposes. The liquid target route faces several scaling challenges but can nonetheless improve the availability of ¹⁰³Pd and consequently aid in widening its utility for radiopharmaceuticals.

Comparison between MCNP and planning system in brachytherapy of cervical cancer

Absorbed doses in uterus during brachytherapy were calculated with MCNP in relevant points and compared with planning system for one patients. MCNP was applied with two different humanoid phantoms in input, ORNL and voxel models, which represent human body in mathematical way. Good agreement between both phantoms, as well as, between MCNP and planning system were found. In addition the doses in critical organs (bladder and colon in this kind of therapy), were calculated and compared with maximal doses in these organs obtained from planning system for 15 other patients. MCNP doses agree well with planning system in points of uterus for those 15 patients, where radioactive source is used to apply. However, there are systematical discrepancies between doses in colon and bladder obtained by MCNP and planning system.

The contemporary use of intracoronary brachytherapy for instent restenosis: A review

In-stent restenosis (ISR) has been a major limitation in interventional cardiology and constitutes nearly 10 % of all percutaneous coronary interventions in the United States. Drug-eluting stent (DES) restenosis proves particularly difficult to manage and poses a high risk of recurrence and repeat intervention. Intra-coronary brachytherapy (IBT) has been traditionally viewed as a potential treatment modality for ISR. However, its use was hindered by procedural complexity, cost, and the advent of newer-generation DES. Recent data suggests promising results regarding IBT for the treatment of resistant DES-ISR. This review addresses the mechanism of action of IBT, procedural details, and associated risks and complications of its use. It will also highlight the available clinical evidence supporting the use of IBT and the future directions of its utilization in the treatment of ISR.

Clinical and treatment characteristics of secondary bladder malignancies following low dose rate brachytherapy for prostate cancer

PURPOSE/OBJECTIVES

To characterize the clinical course and prognosis of bladder malignancies associated with prior prostate brachytherapy SUBJECTS/PATIENTS AND METHODS: We queried our institutional database for patients with bladder cancer (BC) diagnosed between January 2005 and April 2019 who had previously undergone low dose rate (LDR) prostate brachytherapy. Patients diagnosed with BC at least 1 year following LDR prostate brachytherapy with or without external beam radiation therapy were included. Clinical and disease-specific characteristics were abstracted from chart review and survival outcomes were estimated using Kaplan-Meier estimates. We compared the pathologic characteristics and prognosis of secondary BCs in our study cohort to those of BCs diagnosed after prostate cancer managed without radiation reported by the Surveillance, Epidemiology, and End Results (SEER) populational database from 2005 to 2018.

RESULTS

Three hundred seventy-five patients were identified with combined diagnosis of prostate cancer and BC, 51 of whom met inclusion criteria in the study cohort. Median times from brachytherapy to BC diagnosis for the study and SEER cohort were 9.5 ± 4.5 and 6.3 ± 4.1 years, respectively. Compared to the SEER cohort, significantly greater proportion of BC from the study cohort presented with high-grade (study: 78.4%, SEER: 52.3%, P = 0.0008) and with MIBC (Study BC 35.3%, SEER BC: 17.5%, P = 0.0009). The study and the SEER cohort had similar 5-year overall survival (study: 67.9%, SEER: 58.0%, P = 0.1099), and 5-year cancer-specific survival (study: 81.0%, SEER: 82.8%, P = 0.5559). The 5-year progression-free survival for the study cohort was 43.7% (95% CI: 28.8-57.7).

CONCLUSION

Compared to bladder cancers following prostate cancer managed without radiation, bladder malignancies following prostate LDR brachytherapy present with higher grade and are more likely to be muscle invasive. Despite the aggressive presenting features of postprostate brachytherapy BC, there were no differences in overall and cancer-specific survival between the groups.

The role of brachytherapy in treatment of stage I esophageal cancer: A systematic review

PURPOSE

Despite advancements in the early detection of esophageal cancer, optimal radiotherapy methods for treatment of early disease have not yet been determined. Moreover, the benefit of intraluminal brachytherapy on local control or survival remains controversial. We performed a systematic review to establish the role of brachytherapy as boost therapy in stage I esophageal squamous cell carcinoma, and to evaluate associated survival outcomes.

METHODS AND MATERIALS

A systematic search of three bibliographic databases from January 1950 to January 2019 was conducted. All studies investigating brachytherapy for curative intent were included and palliative treatment was excluded. Primary outcomes included overall survival and disease-free survival (DFS). Secondary outcomes included loco-regional control (LRC) and toxicity grades and/or complications. Two reviewers independently abstracted data and evaluated study quality using grading of recommendations assessment, development, and evaluation, pooled results were presented through risk ratios.

RESULTS

A total of 12 retrospective studies met inclusion criteria. The overall quality of evidence yielded a Grade 1C rating (strong recommendation, low quality evidence). Of 525 included patients, 325 patients received both external beam radiation (EBRT), and brachytherapy, 132 underwent EBRT only, and 68 received brachytherapy with and/or without chemoradiation. For patient group treated with EBRT and brachytherapy, 5-year mortality, DFS and LRC were: 43% (27-59%), 63% (49-76%) and 72% (63-80%) respectively. Rates of complications reported included 82.1% Grade 1 esophagitis for a combined external beam radiation and brachytherapy cohort, 12.3% ulcerations, and 3.3% fistulae.

CONCLUSIONS

Brachytherapy as a combined modality is encouraging, given its relative safety and effectiveness. Further prospective analysis using higher quality evidence is warranted to evaluate oncologic outcomes and survival advantage.

90Y-Labeled Gold Nanoparticle Depot (NPD) Combined with Anti-PD-L1 Antibodies Strongly Inhibits the Growth of 4T1 Tumors in Immunocompetent Mice and Induces an Abscopal Effect on a Distant Non-Irradiated Tumor

The effectiveness and normal tissue toxicity of a novel nanoparticle depot (NPD) brachytherapy seed incorporating gold nanoparticles (AuNPs) labeled with β-particle emitting, ⁹⁰Y (termed a "radiation nanomedicine"), were studied for the treatment of 4T1 triple-negative murine mammary carcinoma tumors in Balb/c mice and for inducing an abscopal effect on a distant non-irradiated tumor alone or combined with anti-PD-L1 immune checkpoint antibodies. Balb/c mice with two subcutaneous 4T1 tumors─a primary tumor and a distant secondary tumor were implanted intratumorally (i.t.) in the primary tumor with NPD incorporating 3.5 MBq of ⁹⁰Y-AuNPs (1 × 10¹⁴ AuNPs) or unlabeled AuNPs, alone or combined with systemically administered anti-PD-L1 antibodies (200 μg i.p. three times/week for 2 weeks) or received anti-PD-L1 antibodies alone or no treatment. The primary tumor was strongly growth-inhibited over 14 d by NPD incorporating ⁹⁰Y-AuNPs but only very modestly inhibited by NPD incorporating unlabeled AuNPs. Anti-PD-L1 antibodies alone were ineffective, and combining anti-PD-L1 antibodies with NPD incorporating ⁹⁰Y-AuNPs did not further inhibit the growth of the primary tumor. Secondary tumor growth was inhibited by treatment of the primary tumor with NPD incorporating ⁹⁰Y-AuNPs, and growth inhibition was enhanced by anti-PD-L1 antibodies. Treatment of the primary tumor with NPD incorporating unlabeled AuNPs or anti-PD-L1 antibodies alone had no effect on secondary tumor growth. Biodistribution studies showed high uptake of ⁹⁰Y in the primary tumor [516-810% implanted dose/g (%ID/g)] but very low uptake in the secondary tumor (0.033-0.16% ID/g) and in normal tissues (<0.5% ID/g) except for kidneys (5-8% ID/g). Very high radiation absorbed doses were estimated for the primary tumor (472 Gy) but very low doses in the secondary tumor (0.13 Gy). There was highdose-heterogeneity in the primary tumor with doses as high as 9964 Gy in close proximity to the NPD, decreasing rapidly with distance from the NPD. Normal organ doses were low (<1 Gy) except for kidneys (4 Gy). No normal tissue toxicity was observed, but white blood cell counts (WBC) decreased in tumor-bearing mice treated with NPD incorporating ⁹⁰Y-AuNPs. Decreased WBC counts were interpreted as tumor response and not toxicity since these were higher than that in healthy non-tumor-bearing mice, and there was a direct association between WBC counts and 4T1 tumor burden. We conclude that implantation of NPD incorporating ⁹⁰Y-AuNPs into a primary 4T1 tumor in Balb/c mice strongly inhibited tumor growth and combined with anti-PD-L1 antibodies induced an abscopal effect on a distant secondary tumor. This radiation nanomedicine is promising for the local treatment of triple-negative breast cancer tumors in patients, and these therapeutic effects may extend to non-irradiated lesions, especially when combined with checkpoint immunotherapy.

In vivo dosimetry in pelvic brachytherapy

ADVANCES IN KNOWLEDGE

This paper describes the potential role for in vivo dosimetry in the reduction of uncertainties in pelvic brachytherapy, the pertinent factors for consideration in clinical practice, and the future potential for in vivo dosimetry in the personalisation of brachytherapy.

Design Principles of Hybrid Nanomaterials for Radiotherapy Enhanced by Photodynamic Therapy

Radiation (RT) remains the most frequently used treatment against cancer. The main limitation of RT is its lack of specificity for cancer tissues and the limited maximum radiation dose that can be safely delivered without damaging the surrounding healthy tissues. A step forward in the development of better RT is achieved by coupling it with other treatments, such as photodynamic therapy (PDT). PDT is an anti-cancer therapy that relies on the light activation of non-toxic molecules-called photosensitizers-to generate ROS such as singlet oxygen. By conjugating photosensitizers to dense nanoscintillators in hybrid architectures, the PDT could be activated during RT, leading to cell death through an additional pathway with respect to the one activated by RT alone. Therefore, combining RT and PDT can lead to a synergistic enhancement of the overall efficacy of RT. However, the involvement of hybrids in combination with ionizing radiation is not trivial: the comprehension of the relationship among RT, scintillation emission of the nanoscintillator, and therapeutic effects of the locally excited photosensitizers is desirable to optimize the design of the hybrid nanoparticles for improved effects in radio-oncology. Here, we discuss the working principles of the PDT-activated RT methods, pointing out the guidelines for the development of effective coadjutants to be tested in clinics.

Radiolabeled Nanocarriers as Theranostics-Advancement from Peptides to Nanocarriers

Endogenous targeted radiotherapy is emerging as an integral modality to treat a variety of cancer entities. Nevertheless, despite the positive clinical outcome of the treatment using radiolabeled peptides, small molecules, antibodies, and nanobodies, a high degree of hepatotoxicity and nephrotoxicity still persist. This limits the amount of dose that can be injected. In an attempt to mitigate these side effects, the use of nanocarriers such as nanoparticles (NPs), dendrimers, micelles, liposomes, and nanogels (NGs) is currently being explored. Nanocarriers can prolong circulation time and tumor retention, maximize radiation dosage, and offer multifunctionality for different targeting strategies. In this review, the authors first provide a summary of radiation therapy and imaging and discuss the new radiotracers that are used preclinically and clinically. They then highlight and identify the advantages of radio-nanomedicine and its potential in overcoming the limitations of endogenous radiotherapy. Finally, the review points to the ongoing efforts to maximize the use of radio-nanomedicine for efficient clinical translation.

Anticancer Properties of Curcumin Against Colorectal Cancer: A Review

Colorectal cancer (CRC) is one of the most common and reoccurring diseases, as well as the world’s second largest cause of mortality. Despite existing preventative, diagnostic, and treatment methods, such as chemotherapy, the number of instances rises year after year. As a result, new effective medications targeting specific checkpoints should be developed to combat CRC. Natural compounds, such as curcumin, have shown significant anti-colorectal cancer characteristics among medications that can be used to treat CRC. These chemicals are phenolic compounds that belong to the curcuminoids category. Curcumin exerts its anti-proliferative properties against CRC cell lines in vitro and in vivo via a variety of mechanisms, including the suppression of intrinsic and extrinsic apoptotic signaling pathways, the stoppage of the cell cycle, and the activation of autophagy. Curcumin also has anti-angiogenesis properties. Thus, this review is aimed at emphasizing the biological effect and mode of action of curcumin on CRC. Furthermore, the critical role of these substances in CRC chemoprevention was emphasized.

Application of unlaminated EBT3 film dosimeter for quantification of dose enhancement using silver nanoparticle-embedded alginate film

Purpose.The paper describes the application of unlaminated Gafchromic EBT3 film dosimeter for quantification of dose enhancement using locally synthesized silver nanoparticle-embedded alginate film (AgNPs-Alg film) for nanoparticles-aided radiotherapy.Materials and Methods.AgNPs-Alg film was synthesized and characterized using standard techniques. The unlaminated Gafchromic EBT3 film was specially customized for dosimetric measurement. The dose enhancements due to AgNPs-Alg film was experimentally determined for ISO wide spectrum x-rays series (average energy ranging from 57-137 keV) and 6 and 10 MV x-rays using laminated and unlaminated Gafchromic EBT3 film. The radiation dose of 1 Gy was delivered to a combination of AgNPs-Alg films and EBT3 film.Results.Ultraviolet-Visible spectroscopy of silver nanoparticles shows a surface plasmon resonance peak at 400 nm. The average particle size of 13 ± 2 nm was measured using Atomic Force Microscopy. For unlaminated film, the dose enhancements of 29%, 23%, 14% and 2% was observed for ISO wide spectrum x-rays having average energy of 57, 79, 104 and 137 keV, respectively. The dose enhancement was negligible for 6 and 10 MV x-rays. In the case of laminated film, no significant dose enhancement was measured for all the x-ray energies.Conclusion.The unlaminated Gafchromic EBT3 film can be a suitable choice for the measurement of dose enhancement. Further, silver nanoparticles can be used during nanoparticle-aided radiotherapy when irradiated at low x-ray energy.

The Interplay among Radiation Therapy, Antibiotics and the Microbiota: Impact on Cancer Treatment Outcomes

Radiation therapy has been used for more than a century, either alone or in combination with other therapeutic modalities, to treat most types of cancer. On average, radiation therapy is included in the treatment plans for over 50% of all cancer patients, and it is estimated to contribute to about 40% of curative protocols, a success rate that may reach 90%, or higher, for certain tumor types, particularly on patients diagnosed at early disease stages. A growing body of research provides solid support for the existence of bidirectional interaction between radiation exposure and the human microbiota. Radiation treatment causes quantitative and qualitative changes in the gut microbiota composition, often leading to an increased abundance of potentially hazardous or pathogenic microbes and a concomitant decrease in commensal bacteria. In turn, the resulting dysbiotic microbiota becomes an important contributor to worsen the adverse events caused in patients by the inflammatory process triggered by the radiation treatment and a significant determinant of the radiation therapy anti-tumor effectiveness. Antibiotics, which are frequently included as prophylactic agents in cancer treatment protocols to prevent patient infections, may affect the radiation/microbiota interaction through mechanisms involving both their antimicrobial activity, as a mediator of microbiota imbalances, and their dual capacity to act as pro- or anti-tumorigenic effectors and, consequently, as critical determinants of radiation therapy outcomes. In this scenario, it becomes important to introduce the use of probiotics and/or other agents that may stabilize the healthy microbiota before patients are exposed to radiation. Ultimately, newly developed methodologies may facilitate performing personalized microbiota screenings on patients before radiation therapy as an accurate way to identify which antibiotics may be used, if needed, and to inform the overall treatment planning. This review examines currently available data on these issues from the perspective of improving radiation therapy outcomes.

High-dose-rate plesiotherapy with customized molds in non-melanoma skin cancer: efficacy and safety at 10 years-single institution experience

PURPOSE

Our center adopted high-dose-rate brachytherapy with surface applicators (plesiotherapy) in 2008, creating custom molds to treat irregular areas. This study describes the efficacy and safety outcomes after extensive follow-up in the patients.

METHODS/PATIENTS

We planned the treatment using two computed tomography (CT) scans: the first to delineate the lesion and the second after placing the thermoplastic mold. Fusing the two CT images enables planning of the target volume and pinpointing, where the catheters are in the mold.

RESULTS

Seventy patients received plesiotherapy, either exclusively or following excision in patients with risk factors for recurrence. Those receiving plesiotherapy alone showed a complete response rate of 95.8%, and recurrences occurred in 5.7% at a mean follow-up of 96.2 months. Chronic toxicity appeared in 26.6% of patients, but severity was limited to grade 1 or 2.

CONCLUSIONS

High-dose-rate brachytherapy with customized molds yields a high rate of complete response, with long-term recurrence rates in line with similar studies and an acceptable toxicity rate.

Risk Assessment-Oriented Design of a Needle Insertion Robotic System for Non-Resectable Liver Tumors

Medical robotics is a highly challenging and rewarding field of research, especially in the development of minimally invasive solutions for the treatment of the worldwide leading cause of death, cancer. The aim of the paper is to provide a design methodology for the development of a safe and efficient medical robotic system for the minimally invasive, percutaneous, targeted treatment of hepatocellular carcinoma, which can be extended with minimal modification for other types of abdominal cancers. Using as input a set of general medical requirements to comply with currently applicable standards, and a set of identified hazards and failure modes, specific methods, such as the Analytical Hierarchy Prioritization, Risk Analysis and fuzzy logic Failure Modes and Effect Analysis have been used within a stepwise approach to help in the development of a medical device targeting the insertion of multiple needles in brachytherapy procedures. The developed medical device, which is visually guided using CT scanning, has been tested for validation in a medical environment using a human-size ballistic gel liver, with promising results. These prove that the robotic system can be used for the proposed medical task, while the modular approach increases the chances of acceptance.

Adjuvant brachytherapy for oral squamous cell carcinomas: a single-center experience comparing low-dose and pulsed-dose-rate techniques

OBJECTIVE

This study aims to assess the outcomes of adjuvant interstitial brachytherapy (BT) to the tumor bed for oral cavity squamous cell carcinoma (SCC), and to compare the oncological outcomes and toxicity profile of low-dose-rate (LDR) and pulsed-dose-rate (PDR) BT.

DESIGN

This retrospective single-center study included all patients who underwent postoperative LDR- or PDR-BT to the tumor bed as the sole adjuvant treatment for an oral tongue or floor of the mouth SCC between January 2000 and December 2020.

RESULTS

A total of 79 patients were eligible for this study. The cohort was divided into an LDR group (n = 38) and a PDR group (n = 41). The median time interval between surgery and brachytherapy was 55 days. Median delivered total dose was 55 Gy and median hospital stay was 5 days. Five patients (8.3%) experienced grade 3-4 early toxicity, 2 in the LDR group and 3 in the PDR group. Late toxicities were present in 28 patients (44.4%) and were dominated by grade 1-2 residual pain and dysesthesia, without a statistical difference between the groups. After a median follow-up of 65.1 months, 5‑year local control (LC), disease-free survival (DFS), and overall survival (OS) for the whole cohort were 76.3% (95% CI = 63.4-85.1), 61.6% (95% CI = 49.0-72.0), and 71.4% (95% CI = 58.6-80.8), respectively.

CONCLUSION

Adjuvant BT after excision of oral cavity SCC provides satisfactory oncological outcomes along with good tolerance. In our study, PDR-BT showed similar oncological and functional results to LDR-BT in this indication.

Targeting of radio-enhancing drugs

OBJECTIVE

Toxicity to normal tissue is frequently the dose-limiting factor in the chemotherapy and mixed modality treatments of cancer. If the radio-enhancing drug could be localized at the disease site and released slowly over time, then systemic drug toxicities could be decreased while simultaneously maintaining high drug concentrations in the tumor. These considerations support a role for a sustained release intra-tumoral delivery systems for the delivery of radio-enhancing drugs.

METHODS

Two approaches aimed at achieving the end of localizing the radio-enhancing drug to the tumor are described. First, nanoparticles, which have a prolonged circulation time and facility for enhanced tumor targeting. Structural defects in the walls of the tumor vasculature allow the passage of particles too large to pass through the walls of normal blood vessels. This characteristic of tumor blood vessels, referred to as the enhanced permeability and retention (EPR) effect, allows relatively large entities (typically liposomes, nanoparticles, and macromolecular drugs) to pass from the blood vessels to tumor tissue and as a result nanoparticles accumulate in the tumor while being excluded from normal tissue. Second, biodegradable implanted polymers. In these devices, the radio-enhancing drug is physically trapped within the polymer matrix which is implanted in the tumor. The drug is released as the polymer degrades in response to its local environment. The degradation rate of the polymer device can be adjusted to control the rate of drug release. By this means, the level of radio-enhancing drug can be maintained at the tumor site for the duration of radiation treatment.

RESULTS AND CONCLUSIONS

Results of experiments indicate that for both methods tumor control could be optimized by maintaining the radio-enhancing drug at a useful concentration in the tumor over a period of time compatible with the duration of fractionated radiation treatment. These studies have provided proof of principle support for the further development of this approach. To date, while some of the methods and devices for drug delivery described in this paper have been involved in clinical trials, none have so far been developed for routine clinical application.

Radiation Therapy: Understanding the Patient Experience

Radiation therapy is used as definitive or adjuvant treatment for more than half of all people receiving cancer treatment. The process for the patient spans several months and is demanding physically, mentally, and logistically. Understanding the patient experience from start to finish is important for all oncology nurses, because adherence to the treatment regimen is integral and side effects can occur even after radiation treatment has completed.

Quality assurance tool for determination of position and transit time of a Co-60 source in high dose rate brachytherapy

In this study, three holders were designed, constructed and characterized to perform quality assurance on the source position and transit time in remote afterloading systems with Co-60 sources for high dose rate brachytherapy. The holders design focused on achieving accuracy, low cost, and a time efficient tool for use in clinical settings. Sensitivities greater than 0.6%/mm and maximum precisions better than 0.14 mm for the source position were obtained. The transit time was determined for the holders with a relative precision better than 19%.